
export const addWaterMarker = (str, parentNode, font, textColor) => {

    if (document.getElementById('watermark')) {
        return false
    }
    // 水印文字，父元素，字体，文字颜色
    const can = document.createElement('canvas')
    parentNode.appendChild(can)
    can.width = 200
    can.height = 150
    can.style.display = 'none'
    const cans = can.getContext('2d')
    cans.rotate((-20 * Math.PI) / 180)
    cans.font = font || '20px Georgia'
    cans.fillStyle = textColor || 'rgba(180, 180, 180, 0.3)'
    cans.textAlign = 'left'
    cans.textBaseline = 'middle'
    cans.fillText(str, can.width / 10, can.height / 2)
    // parentNode.style.backgroundImage = 'url(' + can.toDataURL('image/png') + ')'

    const div = document.createElement("div");
    div.id = 'watermark';
    div.style.pointerEvents = "none";
    div.style.top = "0px";
    div.style.left = "0px";
    div.style.position = "fixed";
    div.style.zIndex = "100000";
    div.style.width = document.documentElement.clientWidth + "px";
    div.style.height = document.documentElement.clientHeight + "px";
    div.style.background =
        "url(" + can.toDataURL("image/png") + ") left top repeat";
    document.body.appendChild(div);
}